Two broad methods have been used for making strips of staples. One method involves making wire, forming the wire into individual staples, and uniting the separate staples into a strip by a readily severable tape and adhesive, or into a stick by means of glue. All such staples involve the high cost of producing the wire, and the added cost of the joining materials. In the case of glue, there is a latitude of uncertainty that leads to unintentioned fracturing of a stick of staples into smaller and sometimes useless, often troublesome, pieces. In any case, glue and tape of various kinds sometimes accumulates in a stapler or a tacker, occasionally causing the tool to jam and in some cases requiring periodic cleaning.
According to a second method, strips of staples are formed of sheet metal, each staple beig delineated from its neighbors by grooves or slots leaving connections of reduced cross-section joining the staples, compared to the cross-section of the sheet metal along the common margins of adjacent staples. The strength of such connections is enormously greater than anything encountered in glued staples. As a result, devices used to apply such staples commonly have cutting edges for separating each successive staple from the supply, and the driving power available in such staple-driving devices must be large enough to allow for the severing effort.
An object of the present invention resides in the provision of novel glue-less strips of staples having integral connections between the staples but which are parted from each other except at tiny points of connection, comparable in bond strength to that found in glued staples.
A further object of the invention resides in the provision of novel integrally connected strips of staples of dimensions commonly provided heretofore by making separate staples of formed wire and then joining the staples.
A further object of the invention is to provide novel strips of staples joined to one another by integral connections much smaller in cross-section than the squared thickness of the metal forming the staple, measured perpendicular to the top surface of the strip of staples.
A still further object of the invention resides in novel methods of producing strips of integrally connected staples starting with sheet metal. A specific object is to provide methods of making strips of staples out of sheet metal, where the successive staples have integral connections much smaller than the square of the thickness of the sheet metal.
A further object of the invention resides in novel methods of producing strips of staples having integral connections whose strength approximates the strength of conventional separate staples held together by glue.
A still further object of the invention resides in novel methods of making readily separable staples of sheet metal, the staples having dimensions commonly provided heretofore by making separate staples of wire thereafter united as by means of glue. A further object is to make staples out of sheet metal where the margins of the staples are free of burrs.